<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="js/jquery-3.7.1.js"></script>
</head>
<body>
    <h1>登录成功，欢迎 <span id="u"></span></h1>

    <script>
        let json = sessionStorage.getItem("user");
        let user = JSON.parse(json) ;
        $("#u").text(user.username) ;
    </script>
</body>
</html>